Damping vibration attenuation composite boring cutter and gas turbine wheel disc high-precision deep hole machining method

Abstract

The invention discloses a damping vibration attenuation composite boring cutter and a high-precision deep hole machining method for a gas turbine wheel disc. The damping vibration attenuation composite boring cutter comprises a cutter handle, a boring rod, a cutter head and a gasket. One end of the boring rod is detachably connected with the cutter head, and the other end is fixedly connected with the cutter handle into an integral structure; the boring rod comprises a first boring rod with a solid structure close to one end of the cutter handle and a second boring rod with a hollow structure far away from one end of the cutter handle; a damping vibration attenuation mechanism is arranged in the second boring rod; the cutter handle comprises a conical part and a flange part; the large-diameter end of the conical part is connected with the flange part, and the diameter of the flange part is larger than that of the large-diameter end of the conical part; after the cutter handle is connected with a machine tool spindle, a gap is formed between the flange part and the machine tool spindle, the gasket is arranged in the gap, and the thickness of the gasket is slightly larger than the width of the gap. The numerical control drilling machine has the advantages of being high in rigidity, high in machining precision, good in machining stability, good in surface quality and capable of machining holes with high requirements for hole diameter precision, hole wall surface roughness and cylindricity.

Description

Technical Field

[0001] The invention belongs to the field of mechanical manufacturing, and in particular relates to a damping and vibration-reducing composite boring cutter and a high-precision deep hole processing method for a gas turbine wheel. Background Art

[0002] The rotor disc of a high-power heavy-duty gas turbine is one of the key components of a heavy-duty gas turbine and is crucial to the performance and reliability of the gas turbine.

[0003] High-power heavy-duty gas turbine rotor discs are usually made of high-strength materials such as high-temperature alloys to withstand high temperature, high pressure and high-speed rotation working environments. These discs play a vital role in gas turbines. They are not only responsible for transmitting and withstanding huge mechanical forces, but also directly affect the thermal efficiency, stability and life of the gas turbine. Therefore, high-power heavy-duty gas turbine rotor discs are the core components of gas turbines, and their material selection, manufacturing technology and quality control are directly related to the performance and reliability of gas turbines.

[0004] like Figure 1 As shown, the rotor disc (gas turbine disc 1) of a high-power heavy-duty gas turbine has a large thickness. A large number of high-precision deep holes 2 for mounting tie rods are distributed on the rotor disc of the gas turbine with a circumferential tie rod structure. These high-precision deep holes 2 have high requirements for aperture accuracy, hole wall surface roughness, and cylindricity. At the same time, since the disc material is made of high-strength materials such as high-temperature alloys, it is very difficult to machine high-precision deep holes 2 with high aperture accuracy, hole wall surface roughness, and cylindricity.

[0005] In actual processing, since the turbine wheel 1 is made of high-strength material and the high-precision deep hole 2 is a deep hole with a large aperture, when an ordinary boring tool is used to process the high-precision deep hole 2, the tool is prone to wear, the hole is prone to taper, and the hole wall is prone to vibration marks. Summary of the invention

[0006] The purpose of the present invention is to provide a damping and vibration-reducing composite boring tool with high rigidity, high processing accuracy, good processing stability and good surface quality, as well as a high-precision deep hole processing method for a gas turbine wheel that can process high requirements for hole diameter accuracy, high requirements for hole wall surface roughness and very high requirements for cylindricity, in view of the deficiencies in the prior art.

[0007] The technical purpose of the present invention is achieved by the following technical solutions: A damping and vibration-reducing composite boring tool comprises a tool handle, a boring bar, a tool head and a gasket; one end of the boring bar is detachably connected to the tool head, and the other end of the boring bar is fixedly connected to the tool handle to form an integrated structure; the boring bar comprises a first boring bar of a solid structure close to one end of the tool handle and a second boring bar of a hollow structure away from one end of the tool handle; a damping and vibration-reducing mechanism is provided in the second boring bar; the tool handle comprises a tapered portion and a flange portion; the large-diameter end of the tapered portion is connected to the flange portion, and the diameter of the flange portion is larger than the diameter of the large-diameter end of the tapered portion; after the tool handle is connected to a machine tool spindle, a gap is provided between the flange portion and the machine tool spindle, the gasket is arranged in the gap, and the thickness of the gasket is slightly larger than the width of the gap.

[0008] Preferably, the thickness of the gasket is 0.003-0.01 mm greater than the width of the gap.

[0009] Preferably, the first boring bar is made of hard alloy material, and the second boring bar is made of a high-strength steel cylinder.

[0010] Preferably, the length ratio between the first boring bar and the second boring bar is 1:1-1.5:1.

[0011] A high-precision deep hole machining method for a gas turbine wheel disc comprises the following steps: Step S1: Drilling Place the turbine disc on the CNC machine tool and clamp it, accurately mark the position of the high-precision deep hole on the turbine disc, and use a drill to machine the initial hole on the turbine disc; Step S2: Rough boring The damping vibration reduction composite boring tool is passed through the initial hole in step 1 by a CNC machine tool to complete the tool cutting action and realize the rough boring operation of the high-precision deep hole; Step S3: Fine boring The damping vibration reduction composite boring tool is passed through the high-precision deep hole in step S2 by a numerically controlled machine tool to complete the tool cutting action and realize the precision boring operation of the high-precision deep hole.

[0012] Preferably, the drill bit in step 1 is a composite drill having a positioning drill in the center and a supporting pin in the radial direction.

[0013] Preferably, in step 3, the high-precision deep hole is divided into a plurality of segments with equal lengths; the segments are arranged in order from the tool entrance to the tool exit of the high-precision deep hole; one end of the tool head of the damping and vibration-reducing composite boring tool enters from the tool entrance of the high-precision deep hole without reducing the rotation speed, and gradually reduces the feed speed according to the segmentation sequence; and the cutting density is increased in the rear section of the high-precision deep hole.

[0014] Preferably, the feed speed is reduced by 5-15% for each segment.

[0015] Preferably, the tool head of the damping and vibration-reducing composite boring tool adopts a blade with a narrow chip flute.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The tool holder and the boring bar of the present invention are an integrated structure, which can reduce the number of assembly and connection times of the tool, and can effectively improve the overall rigidity of the boring tool. By setting a damping vibration reduction mechanism, the vibration resistance of the boring tool is improved; by setting a gasket with a thickness slightly larger than the width of the gap, the gap between the end face of the tool holder and the end face of the machine tool spindle is made 0 during use, so that the tool holder can be over-positioned. After the boring tool is installed, dual positioning of the tool holder conical surface and the end face is achieved, which can increase the rigidity by 3.9 times. The adoption of this technical measure improves the rigidity of the entire boring tool, so that the boring tool has the advantages of high processing accuracy, good processing stability, and good surface quality; avoids the occurrence of boring vibration marks under long overhangs, and improves the cylindricity and surface roughness of deep holes; so that it can meet the requirements of high-precision deep holes for processing engine wheel discs, 2. The first boring bar of the present invention is made of hard alloy material, and the second boring bar is made of a high-strength steel cylinder.

[0017] This technical measure can significantly improve cutting efficiency and machining accuracy, while extending the tool life. It can reduce the weight of the entire boring bar, absorb and consume vibration energy, reduce vibration amplitude, and thus improve machining stability and accuracy.

[0018] 3. During the fine boring operation of the present invention, the feed speed is reduced in stages without reducing the rotation speed, and the cutting density is increased in the rear section of the high-precision deep hole, thereby offsetting the reduction in hole size caused by tool wear, effectively improving the cylindricity of the deep hole and reducing the roughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a partial cross-sectional view of the turbine wheel; Figure 2 It is a schematic diagram of the structure of the present invention; Figure 3 yes Figure 2 Schematic diagram of the connection between the tool holder and the machine tool spindle; Figure 4 It is a structural schematic diagram of the drill bit of the present invention; Figure 5 It is a segmented schematic diagram of a high-precision deep hole; Reference numerals: 1—engine wheel; 2—high-precision deep hole; 21—tool inlet; 22—tool outlet; 201—segment one; 202—segment two; 203—segment three; 204—segment four; 205—segment five; 3—damping vibration reduction composite boring tool; 31—tool handle; 311—cone portion; 312—flange portion; 32—boring bar; 321—first boring bar; 322—second boring bar; 3221—damping vibration reduction mechanism; 33—tool head; 34—gasket; 4—Machine tool spindle; 5—drill bit; 51—positioning drill; 52—support pin. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In addition, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0023] Example 1 like Figure 1 — Figure 3As shown, a damping and vibration reduction composite boring tool 3 includes a tool handle 31, a boring bar 32, a tool head 33 and a gasket 4; one end of the boring bar 32 is detachably connected to the tool head 33, and the other end thereof is fixedly connected to the tool handle 31 to form an integrated structure; the boring bar 32 includes a first boring bar 321 of a solid structure close to one end of the tool handle 31 and a second boring bar 322 of a hollow structure away from one end of the tool handle 31; a damping and vibration reduction mechanism 3221 is provided in the second boring bar 322; the tool handle 31 includes a cone portion 311 and a flange portion 312; the large diameter end of the cone portion 311 is connected to the flange portion 312, and the diameter of the flange portion 312 is larger than the diameter of the large diameter end of the cone portion 311; after the tool handle 31 is connected to the machine tool spindle 4, there is a gap between the flange portion 312 and the machine tool spindle 4, the gasket 4 is arranged in the gap, and the thickness of the gasket 4 is slightly larger than the width of the gap. In actual use, the tool handle 31 and the boring rod 32 are an integrated structure, which can reduce the number of assembly and connection times of the tool, and can effectively improve the overall rigidity of the boring tool. By setting the damping vibration reduction mechanism 3221, the vibration resistance of the boring tool is improved; by setting a gasket 4 with a thickness slightly larger than the width of the gap, the gap between the end face of the tool handle 31 and the end face of the machine tool spindle 4 is made to be 0 during use, so that the tool handle 31 is over-positioned. After the boring tool is installed, dual positioning of the conical surface and the end face of the tool handle 31 is achieved, which can increase the rigidity by 3.9 times. The adoption of this technical measure improves the rigidity of the entire boring tool, so that the boring tool has the advantages of high processing accuracy, good processing stability and good surface quality. The adoption of this technical measure also avoids the occurrence of boring vibration marks under long overhangs, improves the cylindricity and surface roughness of deep holes, so that it can meet the requirements of processing high-precision deep holes 2 of engine wheel discs 1. like Figure 2 , Figure 3As shown, in actual use, the tool handle 31 includes a cone 311 and a flange 312; the large diameter end of the cone 311 is connected to the flange 312, and the diameter of the flange 312 is greater than the diameter of the large diameter end of the cone 311. Specifically, the tool handle 31 includes a cone 311 away from one end of the boring bar 32 and a flange 312 close to one end of the boring bar 32 and fixedly connected to the boring bar 32. The end of the tool handle 31 away from the cutter head 33 is used to connect with the machine tool spindle 4; after the tool handle 31 is connected to the machine tool spindle 4, there is a gap between the flange 312 and the machine tool spindle 4, and the gasket 4 is arranged in the gap, and the thickness of the gasket 4 is slightly greater than the width of the gap. In actual use, the material of the gasket 4 is an alloy steel material after quenching and tempering. After quenching and tempering, the alloy steel has good comprehensive mechanical properties, which can make the alloy steel obtain a good combination of strength and toughness, and no plastic deformation occurs after the tool handle 31 is tightened. Therefore, the gasket 4 has high strength and toughness as well as good durability. When preparing the gasket 4, the gap size between the flange portion 312 of the tool handle 31 and the machine tool spindle 4 is first measured by a gauge block or the like, and then the gasket 4 is matched according to the measured gap value. The thickness of the gasket 4 can only be slightly larger than the width of the gap. Specifically, the thickness of the gasket 4 is 0.003-0.01mm larger than the width of the gap, and over-positioning can still be achieved after the tool handle is tightened and the gasket is elastically deformed.

[0024] like Figure 2 As shown, one end of the boring bar 32 is detachably connected to the cutter head 33, and the other end thereof is fixedly connected to the tool handle 31 to form an integrated structure. The boring bar 32 includes a first boring bar 321 of a solid structure near one end of the tool handle 31 and a second boring bar 322 of a hollow structure away from one end of the tool handle 31. The first boring bar 321 is connected to the cutter head 33 at one end away from the second boring bar 321, and the first boring bar 321 is fixedly connected to the second boring bar 32 at one end close to the second boring bar 321; the second boring bar 32 is fixedly connected to the tool handle 31 at one end away from the first boring bar 321. A damping vibration reduction mechanism 3221 is provided in the second boring bar 322. Among them, the damping vibration reduction mechanism 3221 is an existing damping vibration reduction module, etc. The adoption of this technical measure improves the cutting efficiency, machining accuracy, rigidity and stability of the boring tool.

[0025] Specifically, the first boring bar 321 is made of a hard alloy material, and the second boring bar 322 is made of a high-strength steel cylinder. In this embodiment, the length ratio between the first boring bar 321 and the second boring bar 322 is 1:1. The hard alloy used in the first boring bar 321 has the characteristics of high hardness, high wear resistance and high fracture strength. By adopting this technical measure, the cutting efficiency and processing accuracy can be significantly improved, while the service life of the tool can be extended.

[0026] The second boring bar 322 uses high-strength steel with excellent toughness and strength, and can withstand large cutting forces and vibrations. At the same time, by setting a damping vibration reduction mechanism 3221 in the second boring bar 322, the vibration during the cutting process is further reduced. The adoption of this technical measure can reduce the weight of the entire boring bar 32, absorb and consume vibration energy, reduce the vibration amplitude, and thus improve the stability and precision of the processing. In particular, since the high-precision deep hole 2 is a deep hole, the adoption of this technical measure can effectively avoid processing errors and tool damage caused by vibration.

[0027] A high-precision deep hole machining method for a gas turbine wheel disc comprises the following steps: Step S1: Drilling The engine disk 1 is placed on a CNC machine tool and clamped, the position of the high-precision deep hole 2 is accurately marked on the engine disk 1, and an initial hole is machined on the engine disk 1 with a drill bit 5; like Figure 4 As shown, in actual use, the drill bit 5 is a composite drill with a positioning drill 51 in the center and a support pin 52 in the radial direction. The adoption of this technical measure can reduce vibration and deviation during drilling, thereby improving the accuracy and stability of drilling, ensuring the straightness and roundness of the drilled hole; greatly improving the processing efficiency and processing quality. The high-precision deep hole 2 drilled by the drill bit 5 has good straightness, which lays a good foundation for the cylindricality of rough boring and fine boring. At the same time, with the center positioning and radial support pin 52, it is not easy to vibrate under long overhang and large diameter drilling, so that the drilling process can be carried out smoothly.

[0028] Step S2: Rough boring The damping vibration reduction composite boring tool 3 is passed through the initial hole in step 1 by a CNC machine tool to complete the tool cutting action and realize the rough boring operation of the high-precision deep hole 2; Step S3: Fine boring The damping vibration reduction composite boring tool 3 is passed through the high-precision deep hole 2 in step S2 by a numerically controlled machine tool to complete the tool cutting action and realize the precision boring operation of the high-precision deep hole 2.

[0029] like Figure 5 As shown, when the high-precision deep hole 2 is actually finely bored, the high-precision deep hole 2 is evenly divided into multiple segments by length. In this embodiment, the high-precision deep hole 2 is evenly divided into five segments by length. The order of the segments is arranged in the direction from the tool entrance 21 to the tool exit 22 of the high-precision deep hole 2, which are segment one 201, segment two 202, segment three 203, segment four 204 and segment five 205.

[0030] One end of the tool head 33 of the damping and vibration-reducing composite boring tool 3 enters from the tool entrance 21 of the high-precision deep hole 2 without reducing the rotation speed, and gradually reduces the feed speed according to the segmentation sequence, and increases the cutting density in the rear section of the high-precision deep hole 2. In this embodiment, the feed speed is reduced by 10% for each segment. Specifically, in segment one 201, the feed speed of the tool is 100%F; in segment two 202, the feed speed of the tool is 90%F; in segment three 203, the feed speed of the tool is 80%F; in segment four 204, the feed speed of the tool is 70%F; in segment five 205, the feed speed of the tool is 60%F.

[0031] In actual use, the number of segments of the high-precision deep hole 2 and the feed speed of the tool are determined according to the actual boring taper. Due to the deep hole depth, large hole diameter and high material strength of the high-precision deep hole 2, the tool wears quickly when boring once, and the hole diameter of the rear section of the hole gradually decreases, resulting in the deep hole cylindricity not meeting the requirements. By adopting the above technical measures, the feed speed is reduced in sections without reducing the rotation speed, and the cutting density is increased in the rear section of the high-precision deep hole 2, which can offset the reduction in hole diameter caused by tool wear, effectively improve the deep hole cylindricity and reduce roughness.

[0032] In step 3, the tool head 33 of the damping and vibration-reducing composite boring tool 3 adopts a tool head with a narrow chip curling groove. In actual use, the narrow chip curling groove is used for finishing, and the spring-shaped finishing chips are cut. The ultra-finishing blade groove is used for finishing boring, and the chips can be curled into a small-diameter paralyzed shape even at a cutting depth of 0.01mm, so that the chips can be discharged smoothly, and the chips are prevented from exerting interfering radial forces on the boring tool system, thereby improving the cylindricality of deep hole boring and the surface roughness of the hole wall.

[0033] Example 2 The other contents of this embodiment are the same as those of the embodiment 1, except that the length ratio between the first boring bar 321 and the second boring bar 322 is 1.5: 1. Since the cemented carbide used in the first boring bar 321 has the characteristics of high hardness, high wear resistance and high fracture strength, by increasing the proportion of the first boring bar 321 in the entire boring bar 32, the cutting efficiency and machining accuracy of the boring bar 32 are improved, and the service life of the tool is extended.

[0034] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A damping and vibration-reducing composite boring tool, characterized in that: Including tool holder, boring bar, tool head and gasket; One end of the boring bar is detachably connected to the cutter head, and the other end is fixedly connected to the cutter handle to form an integrated structure; The boring bar comprises a first boring bar with a solid structure close to one end of the tool handle and a second boring bar with a hollow structure far from one end of the tool handle; The second boring bar is provided with a damping vibration reduction mechanism; The shank comprises a cone portion and a flange portion; the large diameter end of the cone portion is connected to the flange portion, and the diameter of the flange portion is greater than the diameter of the large diameter end of the cone portion; After the tool handle is connected to the machine tool spindle, a gap is formed between the flange and the machine tool spindle, and the gasket is arranged in the gap. The thickness of the gasket is slightly greater than the width of the gap.

2. The vibration damping composite boring tool according to claim 1, characterized in that: The thickness of the gasket is 0.003-0.01 mm greater than the width of the gap.

3. The vibration damping composite boring tool according to claim 1, characterized in that: The first boring bar is made of hard alloy material, and the second boring bar is made of a high-strength steel cylinder.

4. The vibration damping composite boring tool according to claim 1 or 3, characterized in that: The length ratio between the first boring bar and the second boring bar is 1:1-1.5:

1.

5. A high-precision deep hole machining method for a gas turbine wheel, characterized in that: The following steps are involved: Step S1: Drilling Place the turbine disc on the CNC machine tool and clamp it, accurately mark the position of the high-precision deep hole on the turbine disc, and use a drill to machine the initial hole on the turbine disc; Step S2: Rough boring The damping vibration reduction composite boring tool according to any one of claims 1 to 4 is processed by a numerically controlled machine tool. Pass through the initial hole in step 1 to complete the tool cutting action and realize the rough boring operation of high-precision deep holes; Step S3: Fine boring The damping vibration reduction composite boring tool is passed through the high-precision deep hole in step S2 by a numerically controlled machine tool to complete the tool cutting action and realize the precision boring operation of the high-precision deep hole.

6. The high-precision deep hole machining method for a gas turbine wheel according to claim 5 is characterized in that: The drill bit in step 1 is a composite drill having a positioning drill in the center and a supporting pin in the radial direction.

7. The high-precision deep hole machining method for a gas turbine wheel according to claim 5, characterized in that: In step 3, the high-precision deep hole is divided into a plurality of segments by length; The order of the segments is arranged in the direction from the tool entrance to the tool exit of the high-precision deep hole; One end of the tool head of the damping vibration reduction composite boring tool enters from the tool entrance of the high-precision deep hole without reducing the rotation speed, and gradually reduces the feed speed according to the segmentation sequence, thereby increasing the cutting density in the rear section of the high-precision deep hole.

8. The high-precision deep hole machining method for a gas turbine wheel according to claim 7 is characterized in that: The feed speed is reduced by 5-15% for each segment, which is specifically determined according to the deep hole accuracy.

9. The high-precision deep hole machining method for a gas turbine wheel according to claim 5 or 7, characterized in that: In step 3, the tool head of the damping and vibration-reducing composite boring tool adopts a blade with a narrow chip flute.

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